1. Field of the Invention
The invention is directed in general to a method and apparatus for terminating a fiber optic cable, and more specifically to a ferrule that can be laser welded to a fiber optic cable to securely attach the ferrule to a light-transmitting end of the cable.
2. Discussion of Related Art
For attachment to optical connectors and/or alignment with components such as fiber optic transceivers, fiber optic cables typically need to be terminated. Ferrules for fastening light-transmitting ends of the cables to couplers or connectors are attached to the cables in various manners. Laser welding techniques have been employed in the art to facilitate connections. For example, U.S. Pat. No. 4,859,827 discloses a method in which an optical fiber is bonded to a ferrule by an epoxy adhesive. The ferrule is fitted within a sleeve that is used to attach the fiber to an optical coupler. The sleeve is also used to align the fiber within the coupler, so the ferrule has to be immovably fixed within the sleeve. In one embodiment, thinned regions are formed on the sleeve. A laser beam is directed at the thin region to laser weld the sleeve to the ferrule. Another example is provided by German Patent Document DE19919428, published Nov. 23, 2000. A ferrule is selected to be more transparent than a wrapping surrounding an optical waveguide. Because of the transparency, a laser light penetrates the ferrule to weld the ferrule to the wrapping by a through-melt technique.
In U.S. Pat. No. 6,804,439, a method is described for laser welding a plastic ferrule to a plastic-jacketed optical fiber cable. A layer of material absorptive to radiation at a predetermined wavelength is coated on the optical fiber jacket. The ferrule is selected to be substantially transparent to the predetermined wavelength and receives the cable. When a laser irradiates the assembly, the coating material creates a weld pool extending generally equally into the jacket and ferrule to bond the ferrule to the cable.
These various techniques require additional components such as sleeves and adhesives, ferrules with specific light-transmitting characteristics, or additional fusing material to complete the weld and provide a terminated cable for attachment to optical connectors or couplers.